Propellers have owned propulsion in the seas since roughly 1775. Their reign might soon be ended by what we have learned from Cuttle Fish and other marine animals–none of which have a propeller. Animals with fins and flippers silently and quickly move through the water with an incredible agility to swim forwards, backwards but also vertically, while barely disturbing their surroundings. A new generation of marine engineers are getting close to recreating their efficiency. One startup, Pliant Energy Systems, based in New York, has developed Velox. Propelled by flexible fins, clearly inspired by the undulation of a cuttlefish, it can travel on the surface, underwater, and also across mud or ice, with its fins. There are environmental benefits of the technology– it reduces underwater noise from propellers, and does not disturb the sea floor. Read more in the Journal of Experimental Biology